Means for saving power



1949. is. D. HANCHETT, JR 2,460,883

' MEANS FOR SAVING POWER Filed NOV. 10, 1947 Patented Feb. 8, 1949 UNITED. .STA'l? 2,460,883; MEANS FOR SAVINGPOWER George D. Hanchett-,.Jr., Millburn, N. J.,.assignor to Radio, Corporation ofAmerica; acorporation- My. present invention relates to circuits which are used in radio equipment and more specifically it relates to improvements in providing heating current .for series connected filaments with economy of power and economy of circuit construction. The invention includes a. novel rectifier construction which makes possible the-circuitarrangement.

In circuits of the prior art, commonly associated with heating the filaments of thermionic discharge tubes with power ordinarily dissipated in circuit resistors, it has. been necessary to exclude the rectifierfilament. Ihisexclusion of the rectifier filament was necessary'because of the difiiculties in initially bringing the filament to emission temperature.

Because of the larger relative currentratings of rectifier tubes, their filaments are necessarilyof higher wattage than those of the other tubes usedin conventional receiver circuits. It isclear that greater power economy would result. from utilizing the high wattage rectifier filament as a circuit resistor; than from utilizing the lower wattage-filamentsof other tubes in the same manner.

My invention therefore contemplates utilization of the rectifier filament winding in the place of. a separate circuit resistor thereby providingfor economy inconstruction.

It is accordingly an object of my inventiontoprovide a rectifier tube which is adapted to utilizethe energy ordinarily dissipated in a separate circuit, resistor to heat the cathode, thereby afford ing. economy in operation. Another object of my invention is to provide a-novel-means of, protecting the emission surface.

withthe. discharge path ofthe rectifier tube, and

LI- HiZBQtfOP'thG'. dual .function of bleeder resist-' ance and filamentary heater. Thesecond filamom will maintainthe-emitting suriaceat proper temperature; when the first filament isz'taken out:

of; the circuit. The second, filament may, of

cq lrse besubstituted for any suitable resistance anddo s not. necessarily;harerto-be inzseries with One filamentris connected tothe. supply voltage source through amanual, ther mal era magnetic switch which is opened when theemissionsurface. is brought to operating temperature. Another filament is connected in-series- 2; the rectifier discharge path, as is'exemplified, ing. the specificembodiment used-for purposes; of.i1;- lus-tration.

The features of my invention: whichlconsider novel are set forth with particularity in the-zap":- pended claim-s. The invention itself, however, both as to its organization andits methodpofopa eration, together with additional.objectsrandam' vantages, willbest. be understood from the following descriptionof a specific embodiment, when read in connection-with theaccompanyingdrawings wherein like reference characters. designatev similar parts. throughout the several. views; and. in which:

Figure 1' is a schematic representationofia. air-- .cuit arrangement embodying myinvention,

Figure 2 is a schematic representation ofa dis. charge device constructs-din accordancewith my inventioniandits associated circuitas used with manual switching means,

Figure 3 is a schematic diagram ofmyinvention'. as usedwith an electromagnetic switching means,

Figure 4 is a plan view of one particular manner of construction of the discharge device used. in my invention in conjunctionwith a thermostatic switchingmeans, and;

Figure 5 is a front elevation View of. Figured.

Referring more particularly to-Fignre- 1, there is provided: an alternating voltage; i, one side of" which is connected to the plate 5 of arectifier: tubeA-which has a cathode fiand amultiplicity-of heater filaments, identifiedin this particular embodiment as the starter filament. 3;.and the maintaining filament l. The; other sideoi": the:

supply voltage; may be taken as thevoltage refer-= Y ence pointvandit' is connected to the maintaining filament-l, through a-series. combination comprise. ing a resistor. 9, andthefilaments l5; of such tubes as are usedin associatedoircuits. A common com. nectionismade from the free end: of the maintaming filament l and the cathode 6 of therectia. fier tube, to the capacitor H], which has. its other side connected to the voltage. reference point. Across the terminals of capacitor; lilisconnected a pair of output terminals H. An additional capacitor 8 is, connected'in shunt with-thefilaments-a I16 and. the: resistor 9; Onesideof" the starting; filament 3. is connected through a switchZs. to the. anode siderof the supply. potentialandthe other" psideisconnected through" the resistance a andse ergiaesthe-filamentsz Whemthe cathode :Baoi r rectifier reaches emission temperature, current will flow through the maintaining filament 1. The switch 2 may then be opened to conserve power, for the bleeder current flowing through the maintaining filament 1 is such as to maintain the cathode 6 at emission temperature. The filament itself should for ordinary bleeder circuits obviously beof small current capacity.

Operation of the circuit as shown is preferable for the filaments 16 of the associated tubes will have a chance to warm up more fully before full plate voltage is applied, however, the starter filament 3, if designed to operate at the supply potential may be connected through the switch 2 directly to the supply voltage. A series resistance and a lower voltage starter filament may also be connected directly to the supply if desired, in

voltage drop across the portion of the filament to which the lamp is connected. The indicator lamp may also be used for a dial lamp, and it would additionally function as a rectifier circuit failure indication. The indicating lamp I! may also be used with thermal or magnetically operated switching means. Replacement of the lamp by a relay coil would give one satisfactory method of magnetically operating the switch as adapted to my invention. It is obvious to one skilled in the art that other modifications could be made in I the manner of switching which would not conwhich case the resistance could be of small wattage due to the short time in which it takes filament 3 to heat. The switch may be either manually, relay or thermally operated to open when the maintaining heater filament i, which is connected in the discharge path of the rectifier tube, is brought to such a temperature as to maintain the emission surface at operating temperature by means of the bleeder current. Operation of the switches will be described more completely in the ensuing discussion. 1

Filament l, which is energized by means of bleeder current that flows as soon as the cathode is brought to emission temperature, serves the double function of bleeder resistance and heater filament. Power is conserved by using the heat normally radiated by a bleeder resistance to keep the cathode at emission temperature. This operating filament may have a multiplicity of sections with external connections, each'being used as a distinct portion of the bleeder resistance.

The high potential side of the rectified voltage output is taken from the cathode 6 of the rectifier and the voltage is filtered by the capacitor 10, which is connected across the voltage output. An additional capacitor 8 is connected across the external bleecler portion 9 and the filaments E6 to' plicity of operating filaments I, having distinct external connections. The starter filament is connected to a current source 8, through a switch 2, and an indicating device such as a lamp I1 is connected across a portion of the operating filaments. The energy supply is connected serially with the operating filaments in the discharge path of the tube 4%. The tube functions identically as hereinbefore described, however, operation of the switch 2 is as follows:

When the switch is manually operated, it should be closed when the maintaining filaments I reach operating temperature due to the bleeder current flow through the rectifier tube. An indicating device is needed to show the proper time for closing the switch. This indicator may be in the form of a lamp H, as is illustrated in one specific embodiment of my invention.

The lamp I! will light when the cathode 6 reaches emission temperature causing current to flow through the series filament I, and causing a stitute a departure from the spirit of my invention.

Figure 3 shows a rectifier system employed with my invention in which a magnetically operated switch is used. A rectifier tube 4, having a starter filament 3 and a maintaining filament I, has its anode 5 connected to one side of an alternating supply voltage I, and its cathode 6, connected to theother side through a series circuit comprising its maintaining filament I, a resistor 9, and a relay coil :8. A capacitor H3 or other voltage stabilizing device is connected across the filament and resistor combination. and a pair of output voltage terminals H are connected across the capacitor. Connections are made from the starter filament 3 through the switching contacts 2 of the relay to the supply potential I.

The contacts 2 are closed when the relay coil is cle-energized, allowing initial heating of the cathode from the starter filament 3, which is connected directly to the supply potential.

In operation, the relay coil 18 will be energized when the cathode 6 reaches emission temperature and allows current to flow through the discharge path of the rectifier tube thus opening its contacts 2 and allowing the maintaining filament I to keep the cathode at emission temperature.

An advantage of electromagnetic switching is the comparatively fast operation of the relay in the case of reduced current through the bleeder circuit, which would cause a noticeable period of non-operation in the case of a thermostatic switch due to thermal inertia.

Another advantage of the electromagnet switch is the protection of the cathode emission surface in the case of'a drop in cathode temperature. It is well known in the art that if anode potential is applied during a period at which the cathode is heating or cooling, chunks of the cathode surface may be pulled oil, reducing its efiiciency and causing a premature failure of the tube. The electromagnetic switch would protect the cathode, should the temperature drop for any reason, by quickly energizing the starter filament which will assure a safe operating temperature.

One particular construction of a tube with a thermally operated switch mounted inside the envelope is shown in Figures 4 and 5. The plan view in Figure 4 and the front elevation view in Figure 5 have shown the constructional'arrangement within the tube envelope of theano'de 5, the

connected directly to one side of the supply voltage at the anode 5 by the welded joint l3 and mounted near to and coaxial with the cathode 6. This arm is mounted in such a manner that it is heated initially'and is maintained by the cathode 'B at a temperature high enough to keep its con- 3 tacts 2 open. One side of the filament 1 is connected directly to the switch contact making with the bimetallic arm, preferably at the top of the tube.

The front elevation view shows the manner of externally connecting tube elements at the base. The multiplicity of maintaining filaments is shown in this embodiment for purposes or" illustration as a single filament i.

In operation, the thermal strip 82 is heated by the cathode 6. It is designed in such a manner that the contacts 2 are opened when the cathode reaches proper emission temperature. The thermal properties are such that if the cathode is decreased below safe emission temperature the contacts will close.

My invention in utilizing the rectifier filament as a circuit resistance provides for economy of power in the utilization of the heat developedin such a resistor to heat the cathode. The use of a rectifier filament in such a manner is made possible by the disclosed tube construction. It is to be understood, however, that in the specific embodiment of my invention herein submitted there may be suggested to those skilled in the art certain modifications which will not necessarily constitute a departure from my invention.

Having thus fully described the nature, construction, and operation of my invention, I wish to secure by Letters Patent and claim:

1. In combination an anode, an indirectly heated cathode, a filament arranged to heat said cathode initially to emission temperature, an auxiliary filament arranged to heat said cathode and a circuit connecting said auxiliary filament serially in the discharge path of said cathode and anode to maintain said temperature.

2. In combination an anode, an indirectly heated cathode, a filament arranged to heat said cathode initially to emission temperature, an auxiliary filament arranged to heat said cathode, a switching device, an energizing circuit serially connecting said switching device and said cathode filament, and a circuit connecting said auxiliary filament serially in the discharge path of said anode and cathode to maintain said temperature.

3. In combination, an electricaldischarge tube provided with a thermal switching device opening when said tube reaches operational temperature, an anode, an indirectly heated cathode, and a plurality of filamentary cathode heaters, an electrical energizing circuit serially connecting a first of said filaments and said switch, and an electrical circuit connecting the remainder of said filaments serially in the discharge path of said tube.

4. A thermionic discharge device comprising, in combination, a thermally operated switch, an anode, an indirectly heated cathode, and a plurality of filamentary heaters for heating said cathode, leads from each of said filaments, connections from one lead on the first of said filaments to one side of said switch, a connection from said anode to the other side of said switch, and connections from the remainder of said filament leads, said cathode, and said plate.

5. A thermionic discharge system comprising a sealed envelope containing an anode, an indirectly heated cathode, a thermally operated switch mounted concentrically with said cathode and having one side connected to said anode, and

a plurality of filaments for heating said cathode electrically isolated therefrom, connections to an external electrical energizing circuit from the first of said filaments through said switch, and external connections from the remainder of said filaments and said cathode.

6. A thermionic discharge tube system comprising a sealed envelope containing a cathode, an anode, and a plurality of filamentary heaters for heating said cathode, a switching device having.

a pair of contacts and an electromagnetic operating coil, an external current source connected to a first of said filaments through said switching contacts, and a circuit serially connecting the remainder of said filaments and said electro magnetic coil with a second external current source, said anode and said cathode.

7. An electrical system comprising a thermionic tube tubing a filament, a rectifier tube having an anode, a cathode and a plurality of filaments, an electromagnetic switching means, an external source of current connected to the first of said rectifier filaments through a pair of contacts on said switching means, an electrical circuit connecting the remainder of said filaments in series with a second external current source, said anode and said cathode of said rectifier tube and a circuit connecting the coil of said electromagnetic switch across a portion of said series filaments.

8. An alternating current system comprising a thermionic tube having a filament, a rectifier tube having an anode, a cathode and a plurality of filaments, a switching device, circuit connections supplying the first of said rectifier filaments with heater current through said switching device, a supply voltage a series circuit comprising said supply voltage, the remainder of said filaments, said cathode and said anode, a voltage stabilizing device connect-ed across a portion of said series circuit and a unidirectional output voltage circuit connected to said stabilizing device.

9. In a rectifier system, a tube having a cathode an anode and a plurality of heater filaments, a switching device, a source of potential, an indicating device, a circuit connecting said potential to a first of said heaters through said switch, a circuit connecting the remainder of said filaments in series with a second external current source, said anode and said cathode of said tube, an energizing circuit including said series circuit and said anode and a circuit connecting said indicator device in shunt wth a portion of said series circuit.

10. An electrical system comprising a thermionic discharge tube having a heater filament,

an auxiliary thermionic discharge tube having an anode, an indirectly heated cathode, a starter filament and a maintaining filament each arranged to heat said cathode, a switching device, a supply potential, an energizing circuit connecting said supply potential in series with said heater filament, said switching device and said starter filament, and a maintaining circuit connecting said supply potential in series with said heater filament, said maintaining filament and said anode and said cathode of said auxiliary tube.

GEORGE D. HANCHETT, JR.

No references cited.

Certificate of Correction Patent No. 2,460,883. February 8, 1949.

GEORGE D. HANCHETT, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 19, claim 7, for the word tubing read having;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 7th day of June, A. D. 1949.

THOMAS F. MURPHY,

Am'atant flommiasioner of Patents. 

